Like other aminoglycosides, neomycin is potentially ototoxic, both to vestibular and to auditory functions. Therapy with neomycin otic preparations should be administered cautiously in patients with chronic otitis media or a perforated tympanic membrane. The risk of ototoxicity may be increased if medication enters the middle ear.

The use of medications that are intended for the treatment of otitis externa or other conditions of the external ear canal should generally be avoided, or otherwise approached with caution, in patients with a perforated tympanic membrane due to the risk of toxicity from medication that may get into the middle ear. Caution is also advised in patients with longstanding, chronic otitis media because of the possibility of a perforated tympanic membrane in such patients.

Otic corticosteroids (Includes Cortisporin Otic) ↔ viral infections

The use of otic preparations containing corticosteroids is contraindicated in patients with viral infections of the external canal including varicella and herpes simplex otitis externa. Corticosteroids may decrease host resistance to infectious agents, thus prolonging the course and/or exacerbating the severity of the infection while encouraging the development of new or secondary infection. Normally, corticosteroids may be administered with caution provided it is accompanied by appropriate anti-infective agents. However, otic preparations that are currently available lack effective antiviral agents.

Topical aminoglycosides (Includes Cortisporin Otic) ↔ burns

Topical aminoglycosides should not be used on serious burns. When applied locally, aminoglycosides are generally not absorbed to a significant extent through intact skin but readily absorbed through denuded, burned, or granulating skin. Systemic adverse effects of aminoglycosides include nephrotoxicity and ototoxicity to vestibular and auditory functions. In general, topical aminoglycosides should not be used on large areas of the body or for more than 7 days without medical supervision.